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More accurate static vector block size assertion

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* src/alloc.c: The size of a vector block is bound by the number of
words, not bytes, represented by the pseudovector header RESTSIZE
field, because that limits how big a PVEC_FREE object can be.
This commit is contained in:
Mattias Engdegård 2023-09-16 13:07:42 +02:00
parent 94b1de2774
commit b1881d7dab
1 changed files with 6 additions and 2 deletions
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8
src/alloc.c
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@ -3054,9 +3054,8 @@ enum { VECTOR_BLOCK_SIZE = 4096 };
/* Vector size requests are a multiple of this. */
enum { roundup_size = COMMON_MULTIPLE (LISP_ALIGNMENT, word_size) };
/* Verify assumptions described above. */
/* Verify assumption described above. */
verify (VECTOR_BLOCK_SIZE % roundup_size == 0);
verify (VECTOR_BLOCK_SIZE <= (1 << PSEUDOVECTOR_SIZE_BITS));
/* Round up X to nearest mult-of-ROUNDUP_SIZE --- use at compile time. */
#define vroundup_ct(x) ROUNDUP (x, roundup_size)
@ -3067,6 +3066,11 @@ verify (VECTOR_BLOCK_SIZE <= (1 << PSEUDOVECTOR_SIZE_BITS));
enum {VECTOR_BLOCK_BYTES = VECTOR_BLOCK_SIZE - vroundup_ct (sizeof (void *))};
/* The current code expects to be able to represent an unused block by
a single PVEC_FREE object, whose size is limited by the header word.
(Of course we could use multiple such objects.) */
verify (VECTOR_BLOCK_BYTES <= (word_size << PSEUDOVECTOR_REST_BITS));
/* Size of the minimal vector allocated from block. */
enum { VBLOCK_BYTES_MIN = vroundup_ct (header_size + sizeof (Lisp_Object)) };